Method and Device for Exchange of a Belt

ABSTRACT

The invention relates to a method and a device for the exchange of an old working belt ( 1 ) on a machine for production of a web, for example a paper web, for a new working belt ( 13 ). According to the invention, the exchange is simplified, whereby the track start of the new belt is connected to the old belt, the old belt is made to circulate and thus draws the new belt around such that the new belt adopts the position of the old belt. A joint is then made between two facing ends of the new belt. Said drawing device is embodied such as to permit the old belt for exchange to be pushed from one side of the machine. The device comprises a frame ( 12 ) with two transverse elements ( 12.2, 12.3 ), which enclose the old belt between them in the assembled state. One transverse element ( 12.2 ) supports a roll ( 13.1 ) of the new belt and the other transverse element ( 12.3 ) supports a winding device ( 18 ) for winding on the old belt.

This invention relates to a machine for producing a web made of paper orpaperboard or a film material for example. In this case said inventionrelates to a working belt within such a machine, in particular a wornfelt belt or mesh belt on a paper machine.

An essential component of a paper machine is the press section. Saidpress section has a multiplicity of presses through which felt belts arepassed together with the still wet paper web in order to absorb waterfrom the paper web and discharge the water again in some other position.

The felt belts are exposed to wear to a high degree. Hence they mustoften be exchanged. For this purpose the felt belt is severed when themachine is at a standstill. Then a new felt belt is mounted by wrappingit around the group of rollers—press rollers, guide rollers and thelike—in question. Then the two ends of the felt belt are joined togetherand connected to each other by means of a seam. Nowadays, presses andformers are constructed in cantilever design for the purpose ofexchanging skins, and use is made of seamless meshes and seamless felts.According to the prior art, making a seam is non-problematic and can becarried out easily and quickly. By contrast, mounting a felt beltrequires a certain input of time and labor. The procedure for exchanginga felt belt takes several hours, generally between two and three hours.During this time the machine is at a standstill, which means lostproduction.

It is the object of the invention to disclose a method and a device withwhich it is possible to exchange an old, worn working belt with a newworking belt more quickly, more reliably and with less input of time andlabor, above all when exchanging a felt or a mesh on a paper machine.Also, the quality of the seam should be faultless.

Said object is accomplished by the features of the independent claims.

The essential idea of the invention is the following: The new belt isprovided in roll form. The beginning of the new belt is fixed to the oldbelt. The old belt is first clamped in place and then severed. Then theold belt is wound up, and because of its connection to the new belt ittakes the new belt with it and guides the new belt through theindividual press nips or around the individual rollers until the newbelt has fully adopted the former position of the old belt. Finally, thenew belt is turned into an endless belt or a closed belt loop by makinga seam.

According to an idea which takes the invention further, a belt-pull isfastened to the beginning of the new working belt (felt belt or meshbelt). Said belt-pull generally comprises only one narrow strip which isfixed to the beginning of the working belt, expediently to the middle ofthe belt, meaning half way along its width. The belt-pull can be made ofa completely different material than the working belt. The onlyrequirement is that it can exert a pull. Said belt-pull exists similarlyin roll form; it is rolled onto the new working belt.

Unlike the main idea of the invention, the beginning of the belt-pulland not the beginning of the new working belt is fixed to the oldworking belt. The remaining procedure is the same as with the main idea:The old working belt is fixed, then its beginning is fastened to awinding core. The winding core is set in rotation, whereby the old beltpulls the belt-pull behind it. The advantage of this is that the machinecan now be cleaned without the cleaning work and/or servicing work beingobstructed by the old belt or the new belt. Then the belt-pull isconnected to the new belt (this could also be done sooner). Then thebelt-pull is wound onto the winding core and the new belt is mounted.

The advantages of the invention can be summarized as follows, explainedwith reference to a press section of a paper machine, representative forall cases of application in which a working belt has to be exchanged ona machine for producing a moving web:

-   -   Exchanging an old felt belt with a new one is easy and takes        relatively little time;    -   The construction of the machine is easy to design: The felt belt        is mounted as a belt with two ends and a seam is produced after        mounting; hence the supports of the press section do not have to        be opened, but at the operator end and the driven end they have        bearing structures which can be in one piece and thus do not        require any removable spacers (not a so-called cantilever        design);    -   The new felt belt is treated gently while being mounted, hence        it is free of damage after the mounting;

The felt belt does not have to be draped before being mounted in thepress section, unlike in the method described in “Wochenblatt fürPapierfabrikation” 21/1986;

-   -   The hall crane is not permanently needed for mounting the felt        belt;    -   Positioning the two ends of the new felt belt is performed        exactly and without any special labor input;    -   The inventive device for mounting the new felt belt can be        prepared already while the paper machine is running;    -   The safety of personnel assigned to exchange the felt can be        assured by suitable measures.

The invention will be explained in more detail with reference to thefigures. In the drawing:

FIG. 1 shows, in a side view looking from the operator side, a part ofthe press section of a paper machine with mounting device.

FIG. 2 shows, in an enlarged representation, the mounting deviceaccording to FIG. 1 prepared for exchanging the felt.

FIG. 3 shows the item from FIG. 2 in a position turned through 90degrees.

FIG. 4 shows the item from FIG. 2 with an old and a new felt belt aftersaid belts have been connected to each other.

FIG. 5 shows the item from FIG. 4 after the old felt belt has beensevered and at the beginning if it being wound up.

FIG. 6 shows the item from FIG. 5 with a fully wound-up old felt beltand with a new felt belt shortly before making a seam.

FIG. 7 shows in turn a mounting device similar to the one according toFIG. 6 but designed for a felt belt running at an angle.

FIG. 8 shows a mounting device on which a winding core and a new feltbelt roll are mounted.

FIG. 9 shows a mounting device on which a winding core and a new feltbelt roll are mounted on a horizontal element.

FIG. 10 shows, in a side view, a mounting device which is assigned to afelt loop as part of a press.

FIG. 11 shows in turn, in an enlarged representation, a mounting devicein a view similar to FIG. 10.

FIG. 12 shows the item from FIG. 11, whereby the old felt belt has beenfully or largely removed from the machine.

The following details can be seen in FIG. 1:

The illustrated press section comprises a top felt and a bottom felt.The case in question concerns the top felt, which is referred to in thefollowing as the “old felt belt” 1. The old felt belt 1 has the form ofan endless felt belt loop. The old felt belt 1 enwraps a number of guiderollers 2 to 7. The guide roller 2 is a tensioning guide roller withwhich the old felt belt 1 can be tensioned. The old felt belt passes,together with the bottom felt (which does not need to be gone into anyfurther at this point), through a press formed from two press rollers 8and 9. During operation, a paper web (not illustrated here) runstogether with the two felt belts through the press nip, which is formedfrom the press rollers 8 and 9, and is enclosed hereby like a sandwichbetween the felt belts.

Tubular suction devices 10,11 can also be seen.

The essential item is the mounting device 12, whose details will beconsidered in the following. Said mounting device can be pushed, withthe help of a crane, from the operator end onto the old felt belt 1. Italready carries the new felt belt 13, which has been wound up into aroll 13.1.

The construction of the mounting device 12 can be recognized moreclearly in FIGS. 2 and 3. To be noted in FIG. 3 are the two symbols forthe operator on the left and for the motor on the right corresponding tothe operator end and the driven end. The mounting device is constructedaccordingly from three main elements, namely a rigid vertical connectingelement 12.1, which is situated on the operator end, and two horizontalelements 12.2 and 12.3, which in the built-in state are situatedrespectively above and below the felt belt 1. The length of the twohorizontal elements can be the same size as or somewhat narrower orwider than the width of the felt belt 1. The mounting device 12 is thusopen from the driven end such that it can be pushed onto the felt belt 1(not illustrated here) from the operator end.

The mounting device 12 comprises the following additional elements: Inthe upper horizontal element it carries a bearing for the new felt beltroll 13.1. At least one brake 14 is also there. The brake 14 is used tocheck the tension of the new felt belt 13 while it is being unwound. Theupper horizontal element 12.2 carries in addition a securing device 15with at least one eyelet 15.1 for fastening at least one operator safetybelt.

The lower horizontal element 12.3 has one clamping device 16 and 17respectively on the operator side and the driven side. It also carries awind-up station 18 in the form of a spiked roller.

The new felt belt roll 13.1 can be recognized in FIG. 4. A short lengthof the new felt belt 13 is wound off said new felt belt roll and fixedto the old felt belt 1. If the old felt belt 1 runs around—from left toright in the illustration—then it will take the new felt belt 13 alongwith it and guide it in this case around all the mentioned guide rollers2 to 7 and through the press rollers 8 and 9.

Before this happens, the old felt belt 1 is fixed by means of theclamping devices 16 and 17 and then severed. Then it is fixed by itsbeginning to the spiked roller 18—see FIG. 5. The spiked roller 18 isequipped with a drive. The drive sets the spiked roller in rotation suchthat the old felt belt 1 is wound up. Of course the clamping devices 16and 17 must be released first.

The wound-up state is shown in FIG. 6. The felt belt roll 1.1 formedfrom the old felt belt can be recognized there. Also visible there arethe two ends of the new felt belt 13 which has now been pulled in. Theends of the new felt belt 13 are fixed with the help of the clampingdevices 16 and 17. The rest of the new felt belt 13 is wound off a feltbelt roll. The ends of the new felt belt 13 are laid parallel and closeto each other. A zip fastener (not shown here) is now fixed to the twoends and closed. Then a seam is made, whereupon the clamping devices 16and 17 can be released. Finally the zip fastener is removed. Themounting device 12 has fulfilled its purpose. It is dismantled with thehelp of a crane. In the meantime the old felt belt roll 1.1 was placedon the floor of the paper machine where it can be processed further.

A particularly interesting variant of the inventive method is notpresented in the figures but can be performed without further ado usingthe mounting device shown. In this case provision is made for abelt-pull as was previously mentioned above. The belt-pull is fixed tothe beginning of the new felt belt 13, namely best of all to the middleof said belt's width extension. It is also possible for the new feltbelt 13 to converge to a point at its beginning and for the mentionedbelt-pull to be fixed to said point. Instead of the beginning of the newfelt belt 13 being fixed to the old felt belt 1, now the beginning ofthe belt-pull is fixed to the old felt belt 1—again to the middle of thebelt. The belt-pull has a length which is at least equal to the lengthof the old felt belt 1 or somewhat larger than this length. Theprocedure is essentially the same as for a procedure without the use ofa belt-pull. The advantage of the belt-pull is that the old felt belt 1can be essentially wound up first. Then the machine is free of all skinsand can be cleaned.

The inventive method with the use of a belt-pull now proceeds asfollows:

First the mounting device 12 is fitted with a roll, namely the new feltbelt roll 13.1, onto which the belt-pull is then wound. Thus equipped,the mounting device is moved by means of a crane into the correctposition as shown in FIG. 1.

Then the beginning of the belt-pull is fixed to the old felt belt 1 nodifferently than can be seen in FIG. 4, which shows a direct connectionof the old felt belt 1 and the new felt belt 13.

Then the old felt belt 1 is clamped, severed and fixed to the spikedroller 18. The clamp is then released and the old felt belt 1 wound ontothe spiked roller 18, whereby the belt tension is controlled with thehelp of the brake 14.

As the interim result the old felt belt 1 is fully wound up into a feltbelt roll and the belt-pull is in the position in which the old feltbelt 1 was previously found.

The machine can now be cleaned.

Thereafter the spiked roller 18 is made to rotate again. Consequently,the belt-pull is wound up onto the old felt belt roll 1.1 and the newfelt belt 13 is mounted simultaneously. In other words, the new feltbelt 13 now occupies the position of the old felt belt 1 in that itenwraps all the guide rollers and press rollers as did the old beltpreviously.

Now the two clamping devices 16, 17 are activated. The rest of the newfelt belt 13 is now wound off so that two ends of the new felt belt lieopposite and parallel to each other. A zip fastener is fitted, a seam ismade, the zip fastener is removed and the device dismantled.

The procedure proceeds very quickly. The time it takes lies in themagnitude of 1.5 hours compared to 2 to 3 hours in accordance with theprior art.

In principle it is possible to push the drawing device from either sideof the machine onto the old belt to be exchanged. However, pushing it onfrom the operator end is to be preferred.

The device is expediently designed and arranged such that in the workingstate it adopts the position as shown in FIG. 1. In this case the oldbelt extends through the mounting device 12 in horizontal direction.Also, it is located in the uppermost region of the old belt 1 to beexchanged, meaning between the two uppermost guide rollers 6 and 7.However, the mounting device can also be arranged in a differentposition, e.g. in a lower position or tilted toward the horizontal.

It is also possible to push the mounting device onto a belt 1 running atany angle. The mounting device can then be designed as shown in FIG. 7.The left, horizontal longitudinal support 12.2.1 and the correspondingclamping device 16 can then be arranged lower or higher than the right,horizontal longitudinal support 12.2.2 and the corresponding clampingdevice 17.

On the embodiment according to FIG. 8, a winding core 18 and the newfelt belt roll 13.1 are fitted to an upper horizontal element 12.2,hence above the old felt belt 1 or the new felt belt 13 or thebelt-pull.

The drive for the winding core 18 can be positioned anywhere. Ideally itis arranged in the center of the winding core 18 as illustrated. In thiscase the drive can be a direct drive, for example with a plug-on motor,or a chain drive or cardan shaft drive. Also, the positions of thewinding core 18 and the new felt belt roll 13.1 could be swapped suchthat the winding core 18 is located to the right of the new felt beltroll 13.1.

On the embodiment according to FIG. 9 it is possible to recognize thewinding core 18 and the new felt belt roll 13.1. They are fitted howeverto the lower horizontal element 12.3, hence below the old felt belt 1 orthe new felt belt 13 or a belt-pull. The drive of the winding core 18can be positioned anywhere but again preferably in the center of thewinding core 18 as shown in FIG. 9. Here, too, the positions of thewinding core 18 and the new felt belt roll 13 can be swapped.

It goes without saying that the winding core 18 on the embodimentsaccording to FIG. 8 and FIG. 9 can also be omitted or do not need to befitted in advance.

The press of a paper machine presented in FIG. 10 has two press rollers30, 40 which are enwrapped respectively by a felt belt. In this case itis the lower felt loop formed by the old felt belt 1.

The mounting device 12 can be seen. Said mounting device carries awinding core 18 and the new felt belt roll 13.1. Tubular suction devices10 and 11 are again assigned to the old felt belt 1. The beginning ofthe new felt belt 13 is already connected to the old felt belt 1.

The mounting device 12 is arranged particularly cleverly on thisembodiment. Namely, in this case there is no need to clamp the old belt1 before it is severed. The old belt 1 is prevented simply by gravityfrom moving too far away from the winding core 18 (optional) after saidbelt is severed. The position of the belt end is thus assured throughthe arrangement of the mounting device 12.

On the embodiment in FIG. 11 provision is made for a belt-pull 19 whichis connected at a connection point 20 to the old felt belt 1. Instead ofone belt-pull it is possible for two or more belt-pulls to be providedand, accordingly, for a corresponding number of connection points 20 tobe available. The other end of the belt-pull 19 is connected to a driveunit 21. After the old belt 1 is severed below the connection point 20,the end of the old belt 1 which is not connected to the belt-pull orbelt-pulls 19 moves away from the severance point 20. The old belt canbe wound onto a winding core 18. The dead weight of the old belt 1causes it to be moved out of the machine. If necessary, a pulling forcecan be applied in addition at the free end of the belt—in the figurealongside the winding core 18—by hand or with the help of the drive ofthe winding core 18 for example. The speed with which the old belt 1 isconveyed out of the machine is defined by the drive unit 21 which actsas a brake. Because of its connection to the belt-pull or belt-pulls 19the old belt 1 is not conveyed any faster out of the machine than thedrive unit or drive units allow the belt-pull or belt-pulls to followbehind.

On the embodiment according to FIG. 12, the old belt 1 has been fully orat least largely removed from the machine and wound up onto the windingcore 18 for example. The connection point 20 can be disconnected and thebelt-pull or belt-pulls connected to the drive unit or drive units 21.It is also possible, however, for the belt-pull or belt-pulls to bewound up likewise onto the winding core 18 if one is being used. Theother end of the belt-pull or the belt-pulls is disconnected from thedrive unit or drive units 21 and connected to the beginning of the newbelt 13, which is on the roll 13.1. See the connection point 22. The newbelt 13 is pulled into the machine by activating the drive unit or driveunits (either 18 or 21). When the new belt 13 has adopted the formerposition of the old belt 1, the belt loop is rendered endless by makinga seam.

1. Method for exchanging an old felt belt or mesh belt or other workingbelt with a new belt provided in roll form (13.1) on a machine forproducing a paper web or a paperboard web or some other web made fromanother flat material; characterized by the following features: 1.1 thebeginning of the new belt (13) is fixed to the old belt (1); 1.2 theposition of the old belt (1) is secured in front of the fixing pointlooking in the mounting direction; 1.3 the old belt (1) is coupleddirectly or indirectly to a drive unit; the secured positioning of theold belt (1) is canceled; 1.5 the drive unit is activated, whereby theold belt (1) takes the new belt (13) with it until the new belt (13) hasadopted the former position of the old belt (1); 1.6 the positions ofthe beginning and/or the end of the new belt (13) are secured prior toconnecting; 1.7 an endless belt loop is formed from the new belt (13) bymaking a seam; 1.8 the fixing of the new belt (13) to the old belt (1)is canceled.
 2. Method for exchanging an old felt belt or mesh belt orother working belt with a new belt on a machine for producing a paperweb or a paperboard web or a web made from another flat material;characterized by the following features: 2.1 the new belt (13) isprovided in roll form (13.1); 2.2 the beginning of at least onebelt-pull is fixed to the old belt (1); the position of the old belt (1)is secured in front of the fixing point looking in the mountingdirection; the belt-pull or belt-pulls are fixed to the old belt (1);2.5 the secured positioning of the old belt (1) is canceled; 2.6 thedrive unit is activated, whereby the old belt (1) takes the belt-pull orbelt-pulls with it until the required region is free of the old and/ornew belt (1) or (13); 2.7 the end of the belt-pull or belt-pulls isfirmly connected to the beginning of the new belt (13); 2.8 the driveunit is activated or remains activated, whereby the belt-pull orbelt-pulls take the new belt (13) with them until the new belt (13) hasadopted the former position of the old belt (1); 2.9 the positions ofthe beginning and/or the end of the new belt (13) are secured prior toconnecting; 2.10 an endless belt loop is formed from the new belt (13)by making a seam; 2.11 the fixing of the belt-pull or belt-pulls to thenew belt (13) is canceled;
 3. Method according to claim 1, characterizedin that the old belt (1) is wound up into a belt roll (1.1).
 4. Methodaccording to claim 2, characterized in that the belt-pull is wound upseparately from or together with the old belt (1).
 5. Method accordingto claim 1, characterized in that a pulling force can be appliedrespectively to the old belt (1) and/or to the new belt (13) and/or tothe belt-pull or belt-pulls for the purpose of exchanging the belt. 6.Method according to claim 2, characterized by the following features:6.1 a pulling force is applied to the belt-pull or belt-pulls; 6.2 thefree end of the old belt (1), which is not connected to the belt-pull orbelt-pulls, is lowered by its own dead weight and/or by an additionalaction of force such that the belt-pull or belt-pulls on the other endof the belt (1) are inserted into the machine again.
 7. Method accordingto claim 1, characterized in that the machine is cleaned after windingup the old belt (1) and, where applicable, the belt-pull into a beltroll (1.1).
 8. Method according to claim 1, characterized in that thebelt tension of the belts is established or controlled during thewinding up.
 9. Method according to claim 1, characterized in that inorder to make a seam the two ends of the new belt (13) are broughttogether and fitted with a zip fastener and that the seam is then madeand the zip fastener removed again.
 10. Device for exchanging an oldfelt belt or mesh belt or other working belt with a new belt on amachine for producing a paper web or a paperboard web or a web made fromanother flat material, characterized by the following components: 10.1there is provided a frame (12) comprising at least one first transverseelement (12.2) located between two longitudinal elements (12.2.1,12.2.2); 10.2 the transverse element (12.2) carries a bearing forreceiving a roll (13. 1) of the new belt in a position in which the axisof the roll (13.1) extends transverse to the running direction of theold belt (1); 10.3 there is provided an apparatus for making a seambetween two adjacent ends of the new belt (13); 10.4 there is providedat least one drive device for the old belt (1) and/or for the new belt(13) and/or for a belt-pull or belt-pulls.
 11. Device according to claim10, characterized in that there is provided a brake (14) forestablishing or controlling the belt tension during mounting.
 12. Deviceaccording to claim 10, characterized in that there is provided on one ofthe transverse elements (12.2, 12.3) a winding core (18) for winding upthe old belt (1).
 13. Device according to claim 12, characterized inthat the winding core comprises a spiked roller.
 14. Device according toclaim 10, characterized in that one of the transverse elements(12.2,12.3) is constructed as a seam platform.
 15. Device according toclaim 10, characterized in that the length of the belt-pull is greaterthan or equal to the length of the old belt (1).
 16. Device according toclaim 10, characterized in that the two transverse elements (12.2, 12.3)and the segment (12.1) joining them together has a C-shaped form lookingin the web running direction.
 17. Device according to claim 16,characterized in that the two transverse elements (12.2, 12.3) and thesegment (12.1) can be turned into a closed frame by an additionalsegment.
 18. Device according to claim 1, characterized in that thedevice is permanently installed.
 19. Device according to claim 1,characterized in that the device is mobile.
 20. Device according toclaim 10, characterized in that at least one bearing is provided toreceive a roll (13.1) of the new belt (13).